<script setup lang="ts">
import { useMouseInElement } from '@vueuse/core';
import { computed, ref } from 'vue';

defineProps({ imageList: { type: Array<string>, required: true } });

// 大图显示小图切换功能
const activeIndex = ref<number>(0);
const toggleActiveIndex = function (index: number) {
    activeIndex.value = index;
};

// 放大镜功能
const target = ref(null);
const { elementX, elementY, isOutside } = useMouseInElement(target);
const position = computed(() => {
    // 鼠标未进入图片则不修改
    if (isOutside.value) return { left: 0, top: 0 };
    // 计算放大区域偏移
    let left, top;
    if (elementX.value < 100) left = 0;
    else if (elementX.value > 300) left = 200;
    else left = elementX.value - 100;
    if (elementY.value < 100) top = 0;
    else if (elementY.value > 300) top = 200;
    else top = elementY.value - 100;
    return { left, top };
});
</script>

<template>
    <div class="goods-image">
        <!-- 左侧大图-->
        <div class="middle" ref="target">
            <img :src="imageList[activeIndex]" alt="" />
            <!-- 蒙层小滑块 -->
            <div class="layer" :style="{ left: `${position.left}px`, top: `${position.top}px` }" v-show="!isOutside">
            </div>
        </div>
        <!-- 小图列表 -->
        <ul class="small">
            <li v-for="(img, index) in imageList" :key="img" @mouseenter="toggleActiveIndex(index)"
                :class="{ active: index === activeIndex }">
                <img :src="img" alt="" />
            </li>
        </ul>
        <!-- 放大镜大图 -->
        <div class="large" :style="[
            {
                backgroundImage: `url(${imageList[activeIndex]})`,
                backgroundPositionX: `${-position.left}px`,
                backgroundPositionY: `${-position.top}px`,
            },
        ]" v-show="!isOutside"></div>
    </div>
</template>

<style scoped lang="scss">
.goods-image {
    width: 480px;
    height: 400px;
    position: relative;
    display: flex;

    .middle {
        width: 400px;
        height: 400px;
        background: #f5f5f5;
    }

    .large {
        position: absolute;
        top: 0;
        left: 412px;
        width: 400px;
        height: 400px;
        z-index: 500;
        box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        background-repeat: no-repeat;
        // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
        background-size: 800px 800px;
        background-color: #f8f8f8;
    }

    .layer {
        width: 200px;
        height: 200px;
        background: rgba(0, 0, 0, 0.2);
        // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
        left: 0;
        top: 0;
        position: absolute;
    }

    .small {
        width: 80px;

        li {
            width: 68px;
            height: 68px;
            margin-left: 12px;
            margin-bottom: 15px;
            cursor: pointer;

            &:hover,
            &.active {
                border: 2px solid $xtxColor;
            }
        }
    }
}
</style>